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排序方式: 共有156条查询结果,搜索用时 765 毫秒
101.
RG Lockie AB Schultz SJ Callaghan CA Jordan TM Luczo MD Jeffriess 《Biology of sport / Institute of Sport》2015,32(1):41-51
There is little research investigating relationships between the Functional Movement Screen (FMS) and athletic performance in female athletes. This study analyzed the relationships between FMS (deep squat; hurdle step [HS]; in-line lunge [ILL]; shoulder mobility; active straight-leg raise [ASLR]; trunk stability push-up; rotary stability) scores, and performance tests (bilateral and unilateral sit-and-reach [flexibility]; 20-m sprint [linear speed]; 505 with turns from each leg; modified T-test with movement to left and right [change-of-direction speed]; bilateral and unilateral vertical and standing broad jumps; lateral jumps [leg power]). Nine healthy female recreational team sport athletes (age = 22.67 ± 5.12 years; height = 1.66 ± 0.05 m; body mass = 64.22 ± 4.44 kilograms) were screened in the FMS and completed the afore-mentioned tests. Percentage between-leg differences in unilateral sit-and-reach, 505 turns and the jumps, and difference between the T-test conditions, were also calculated. Spearman''s correlations (p ≤ 0.05) examined relationships between the FMS and performance tests. Stepwise multiple regressions (p ≤ 0.05) were conducted for the performance tests to determine FMS predictors. Unilateral sit-and-reach positive correlated with the left-leg ASLR (r = 0.704-0.725). However, higher-scoring HS, ILL, and ASLR related to poorer 505 and T-test performance (r = 0.722-0.829). A higher-scored left-leg ASLR related to a poorer unilateral vertical and standing broad jump, which were the only significant relationships for jump performance. Predictive data tended to confirm the correlations. The results suggest limitations in using the FMS to identify movement deficiencies that could negatively impact athletic performance in female team sport athletes. 相似文献
102.
Mechanism and energetics of proton translocation by the respiratory heme-copper oxidases 总被引:1,自引:0,他引:1
Recent time-resolved optical and electrometric experiments have provided a sequence of events for the proton-translocating mechanism of cytochrome c oxidase. These data also set limits for the mechanistic, kinetic, and thermodynamic parameters of the proton pump, which are analysed here in some detail. The analysis yields limit values for the pK of the "pump site", its modulation during the proton-pumping process, and suggests its identity in the structure. Special emphasis is made on side-reactions that may short-circuit the pump, and the means by which these may be avoided. We will also discuss the most prominent proton pumping mechanisms proposed to date in relation to these data. 相似文献
103.
Leo AB Joosten Erik Lubberts Monique MA Helsen Tore Saxne Christina JJ Coenen-de Roo Dick Heinegård Wim B van den Berg 《Arthritis research & therapy》1999,1(1):81-11
Destruction of cartilage and bone are hallmarks of human rheumatoid arthritis (RA), and controlling these erosive processes
is the most challenging objective in the treatment of RA. Systemic interleukin-4 treatment of established murine collagen-induced
arthritis suppressed disease activity and protected against cartilage and bone destruction. Reduced cartilage pathology was
confirmed by both decreased serum cartilage oligomeric matrix protein (COMP) and histological examination. In addition, radiological
analysis revealed that bone destruction was also partially prevented. Improved suppression of joint swelling was achieved
when interleukin-4 treatment was combined with low-dose prednisolone treatment. Interestingly, synergistic reduction of both
serum COMP and inflammatory parameters was noted when low-dose interleukin-4 was combined with prednisolone. Systemic treatment
with interleukin-4 appeared to be a protective therapy for cartilage and bone in arthritis, and in combination with prednisolone
at low dosages may offer an alternative therapy in RA. 相似文献
104.
Radim Cegan Gabriel AB Marais Hana Kubekova Nicolas Blavet Alex Widmer Boris Vyskot Jaroslav Doležel Jan Šafář Roman Hobza 《BMC plant biology》2010,10(1):180
Background
The evolution of sex chromosomes is often accompanied by gene or chromosome rearrangements. Recently, the gene AP3 was characterized in the dioecious plant species Silene latifolia. It was suggested that this gene had been transferred from an autosome to the Y chromosome. 相似文献105.
Sandra I Vieira Sandra Rebelo Hermann Esselmann Jens Wiltfang James Lah Rachel Lane Scott A Small Sam Gandy Edgar F da Cruz e Silva Odete AB da Cruz e Silva 《Molecular neurodegeneration》2010,5(1):1-21
Background
Retrograde transport of several transmembrane proteins from endosomes to the trans-Golgi network (TGN) occurs via Rab 5-containing endosomes, mediated by clathrin and the recently characterized retromer complex. This complex and one of its putative sorting receptor components, SorLA, were reported to be associated to late onset Alzheimer's disease (AD). The pathogenesis of this neurodegenerative disorder is still elusive, although accumulation of amyloidogenic Abeta is a hallmark. This peptide is generated from the sucessive β- and γ- secretase proteolysis of the Alzheimer's amyloid precursor protein (APP), events which are associated with endocytic pathway compartments. Therefore, APP targeting and time of residence in endosomes would be predicted to modulate Abeta levels. However, the formation of an APP- and retromer-containing protein complex with potential functions in retrieval of APP from the endosome to the TGN had, to date, not been demonstrated directly. Further, the motif(s) in APP that regulate its sorting to the TGN have not been characterized.Results
Through the use of APP-GFP constructs, we show that APP containing endocytic vesicles targeted for the TGN, are also immunoreactive for clathrin-, Rab 5- and VPS35. Further, they frequently generate protruding tubules near the TGN, supporting an association with a retromer-mediated pathway. Importantly, we show for the first time, that mimicking APP phosphorylation at S655, within the APP 653YTSI656 basolateral motif, enhances APP retrieval via a retromer-mediated process. The phosphomimetic APP S655E displays decreased APP lysosomal targeting, enhanced mature half-life, and decreased tendency towards Abeta production. VPS35 downregulation impairs the phosphorylation dependent APP retrieval to the TGN, and decreases APP half-life.Conclusions
We reported for the first time the importance of APP phosphorylation on S655 in regulating its retromer-mediated sorting to the TGN or lysosomes. Significantly, the data are consistent with known interactions involving the retromer, SorLA and APP. Further, these findings add to our understanding of APP targeting and potentially contribute to our knowledge of sporadic AD pathogenesis representing putative new targets for AD therapeutic strategies. 相似文献106.
The pH dependence of electron and proton re-equilibration upon CO photolysis from two-electron-reduced aa3 oxidase was followed by time-resolved electrometry and optical spectroscopy. Optical spectroscopy on soluble Paracoccus denitrificans enzyme at alkaline pH revealed a slow (1 ms) component of electron re-equilibration coupled to the release of protons from the catalytic site. In the work [Br?ndén, M., et al. (2003) Biochemistry 42, 13178-13184], it was proposed that this proton is released from a water molecule in the catalytic site, located deep in the membrane dielectric. Movement of charged particles such as protons across the dielectric should create an electric potential. However, recording of the time course of the potential generation did not show any potential development in the millisecond time domain, but instead, potential generation was found with an apparent time constant of 50-100 micros. This potential was generated upon proton release from the level of the binuclear catalytic site through the K-channel, because mutation in this channel abolishes the potential generation altogether. The apparent inconsistency between results from optical spectroscopy and electrometry was solved by optical experiments on the membrane-incorporated enzyme. Reconstituting the enzyme into proteoliposomes speeds up the slow electron redistribution process by a factor of 10 and shows the same time constant as potential generation. The possible mechanism of such dramatic change in the rate of proton transfer is discussed. 相似文献
107.
Bohnet S Ananthakrishnan R Mogilner A Meister JJ Verkhovsky AB 《Biophysical journal》2006,90(5):1810-1820
Protrusion, the first step of cell migration, is driven by actin polymerization coupled to adhesion at the cell's leading edge. Polymerization and adhesive forces have been estimated, but the net protrusion force has not been measured accurately. We arrest the leading edge of a moving fish keratocyte with a hydrodynamic load generated by a fluid flow from a micropipette. The flow arrests protrusion locally as the cell approaches the pipette, causing an arc-shaped indentation and upward folding of the leading edge. The effect of the flow is reversible upon pipette removal and dependent on the flow direction, suggesting that it is a direct effect of the external force rather than a regulated cellular response. Modeling of the fluid flow gives a surprisingly low value for the arresting force of just a few piconewtons per micrometer. Enhanced phase contrast, fluorescence, and interference reflection microscopy suggest that the flow does not abolish actin polymerization and does not disrupt the adhesions formed before the arrest but rather interferes with weak nascent adhesions at the very front of the cell. We conclude that a weak external force is sufficient to reorient the growing actin network at the leading edge and to stall the protrusion. 相似文献
108.
Cytochrome bd is a terminal quinol:O 2 oxidoreductase of the respiratory chain of Escherichia coli. The enzyme generates protonmotive force without proton pumping and contains three hemes, b 558, b 595, and d. A highly conserved glutamic acid residue of transmembrane helix III in subunit I, E107, was suggested to be part of a transmembrane pathway delivering protons from the cytoplasm to the oxygen-reducing site. When E107 is replaced with leucine, the hemes are retained but the ubiquinol-1-oxidase activity is lost. We compared wild-type and E107L mutant enzymes during single turnover using absorption and electrometric techniques with a microsecond time resolution. Both wild-type and E107L mutant cytochromes bd in the fully reduced state bind O 2 rapidly, but the formation of the oxoferryl species in the mutant is dramatically retarded as compared to the wild type. Intraprotein electron redistribution induced by the photolysis of CO bound to ferrous heme d in the one-electron-reduced wild-type enzyme is coupled to the membrane potential generation, whereas the mutant cytochrome bd shows no such potential generation. The E107L mutation also causes decrease of midpoint redox potentials of hemes b 595 and d by 25-30 mV and heme b 558 by approximately 70 mV. There are two protonatable groups redox-linked to hemes b 595 and d in the active site, one of which has been recently identified as E445, whereas the second group remains unknown. Here we propose that E107 is either the second group or a key residue of a proposed proton delivery pathway leading from the cytoplasm toward this second group. 相似文献
109.
Fanni Aspetsberger Matthias Zabel Timothy Ferdelman Ulrich Struck Andreas Mackensen Astrid Ahke Ursula Witte - Present address: University of Aberdeen Aberdeen AB TZ UK 《Marine Biology Research》2007,3(5):342-356
The benthic community in continental slope and deep-sea sediments of the Benguela Upwelling System was supplied with 13C-labelled organic matter (OM) of two different qualities using a benthic chamber lander. Freeze-dried cultures of Skeletonema costatum served as 'fresh' OM. 'Altered' OM of the same material had been additionally dialysed to remove low-molecular weight compounds. In order to investigate the benthic response pattern, mineralization of labelled OM, uptake by macrofauna and incorporation into bacteria were followed over 18-36 h. Total oxygen uptake was not affected beyond natural variation by the OM addition. Mineralization dominated the 13C-labelled phytodetritus processing, constituting 71-95% of the total processed OM. Bacterial incorporation of phytodetrital carbon exceeded macrofaunal uptake at all stations. Stations situated in a major centre of OM deposition showed phytodetritus processing rates on average twice as high as outside the depocentre. Phytodetritus processing was 1.5, 2.5 and 4.3 times higher for fresh than for altered OM at 605, 1019 and 1335 m water depth, respectively. Our observations clearly indicate the importance of OM quality on mineralization rates. 相似文献
110.
Therien Denis AB Hou Renjie Lagugné-Labarthet François 《Plasmonics (Norwell, Mass.)》2020,15(2):507-515
Plasmonics - Nanostructured conductive surfaces have been exploited for a variety of applications in photonics and optical sensing due to the broad spectral tunability of the localized surface... 相似文献